To both their investors and their bosses, Wall Street firms have become shockingly opaque. But the problem isn’t new. It dates back at least to the early 1980s when one firm, Salomon Brothers, suddenly began to make more money than all the other firms combined. (Go look at the numbers: They’re incredible.)

The profits came from financial innovation — mainly in mortgage securities and interest-rate arbitrage. But its CEO, John Gutfreund, had only a vague idea what the bright young things dreaming up clever new securities were doing. Some of it was very smart, some of it was not so smart, but all of it was beyond his capacity to understand.

Ever since then, when extremely smart people have found extremely complicated ways to make huge sums of money, the typical Wall Street boss has seldom bothered to fully understand the matter, to challenge and question and argue.

This isn’t because Wall Street CEOs are lazy, or stupid. It’s because they are trapped. The Wall Street CEO can’t interfere with the new new thing on Wall Street because the new new thing is the profit center, and the people who create it are mobile.

Anything he does to slow them down increases the risk that his most lucrative employees will quit and join another big firm, or start their own hedge fund. He isn’t a boss in the conventional sense. He’s a hostage of his cleverest employees. …